370 research outputs found
Influential Article Review - Omni-channel General Merchandise Fulfillment Networks
This paper examines logistics. We present insights from a highly influential paper. Here are the highlights from this paper: The growing importance of online sales means that traditional bricks-and-mortar retailers need to create new distribution systems to serve customers through multiple channels. Building an effective and efficient omni-channel (OC) distribution system, however, leads to multiple challenges. The questions arise for example, from where online orders should be fulfilled, how delivery and return processes can be organized, and which context-specific OC distribution systems exist. Answering these questions retail research and practice require an overall view of the distribution concepts for direct-to-customer and store deliveries in OC retailing, including the associated return processes. This overall picture is still missing in the literature. We conducted an exploratory study to close this observable gap in the literature. This exploratory study is based on semi-structured interviews with major OC retailers in German-speaking countries and was complemented by market data research and discussions with further experts in the field of OC retailing. Based on the results of the study, the forward distribution system in OC retailing is characterized by the sources (supplier DCs, retailer DCs, stores) and destinations (home, store) which describe the options for store delivery, home delivery, and store pickup. Return processes are likewise characterized by the sources (store, home) and destinations (store, DC, return center). This framework forms the foundation for analyzing contextual criteria, identifying when the different conceptual designs are applied, determining industry-specific characteristics, and illustrating ways to further advance OC retailing. The present paper, therefore, contributes to the literature in three main areas: (1) it identifies and systematizes the forward and backward concepts in OC retailing, (2) it reveals application and development areas for achieving excellence in OC fulfillment and logistics, and (3) shows the need for developing sector- and context-specific OC distribution systems. For our overseas readers, we then present the insights from this paper in Spanish, French, Portuguese, and German
CALIDAD DE SUELOS PARA LA AGRICULTURA EN LOS DISTRITOS DE LUYA VIEJO, CONILA, COHECHAN, SAN CRISTOBAL DEL OLTO DE LA PROVINCIA DE LUYA
La presente investigación tuvo como objetivo determinar la calidad de suelos para la agricultura en los distritos de Luya viejo, Conila, Cohechán y San Cristobal del Olto de la provincia de Luya, región Amazonas - Perú, llevándose a cabo en la Universidad Nacional Toribio Rodríguez de Mendoza de Amazonas, Asimismo se realizaron una serie de análisis donde a cada muestra se determinó las caracterizaciones: Nitrógeno, Fosforo, Potasio, Calcio, Magnesio, Azufre, pH y Materia Orgánica, se usaron estimaciones porcentuales e interválica para las observaciones de cada característica evaluada, las mismas que fueron comparadas con los resultados de estudios anteriores y bibliografía especializada. Para la realización de la presente investigación se realizaron calicatas de 30 cm de profundidad ya que los cultivos instalados no requieren de mayor profundidad, se extrajeron muestras provenientes de los distritos de: Luya Viejo, Conila, Cohechan, y San Cristobal del Olto. Estos parámetros encontrados a través del análisis de suelo, donde los métodos que se emplearon para los análisis químicos cuantitativos, para estos elementos; y en donde se trató de combinar los métodos de análisis por vía clásica y por vía instrumental que permitieron determinar la fertilidad del mismo; encontrándose además: Nitrógeno entre 14 y 20 kg/ha; Fósforo entre 4 y 9 kg/ha; Potasio entre 65 y 120 kg/ha; Calcio entre 45 y 80 kg/ha; Magnesio entre 0 y 0,5 kg/ha; Azufre entre 0 y 0,5 kg/ha; pH entre 6,50 y 7,20 kg/ha y Materia Orgánica entre 2,24 y 3.12 kg/ha. De los análisis practicados a las muestras de los diversos distritos en estudio se demostró que los suelos más calcáreos se encuentran en San Cristobal del Olto, lo cual facilita la siembra de alfalfa. De los 4 distritos en estudio el suelo de mejor calidad, por los nutrientes, se encuentra en San Cristóbal del Olto y el de menor concentración de nutrientes en Conil
Associations between animal and herd management factors, serological response to three respiratory pathogens and pluck lesions in finisher pigs on a farrow-to-finish farm
peer-reviewedBackground
Serological screening is a common method to monitor antibody response to pathogen exposure, but results could vary due to several factors. This study aimed to quantify animal and management related factors associated with variation in antibody levels in finisher pigs at slaughter, in an Irish farrow-to-finish farm endemically infected with Actinobacillus pleuropneumonia (App), Mycoplasma hyopneumoniae (Mhyo) and swine influenza virus (SIV). A second objective was to estimate differences in antibody levels in pigs presenting pluck lesions. This was an observational study whereby pigs were managed as per routine farm practice. Data on sow parity, number of born alive (NBA) pigs per litter, cross-fostering status, birth and weaning body weight were recorded from 1016 pigs born from one farrowing batch. At slaughter, blood samples were collected for serological analysis and pigs were inspected for presence of enzootic pneumonia (EP)-like lesions, pleurisy, pericarditis and heart condemnations. Pigs were retrospectively classified into three production flows, depending on time spent in each production stage: flow 1 (F1; pigs followed the normal production flow); flow 2 (F2; pigs which were delayed by 1 week from advancing forward); and flow 3 (F3; pigs delayed by > 1 week from advancing forward). A nested case-control design was applied by matching pigs from each flow by sow parity, birth weight and NBA.
Results
Pigs born from primiparous sows had higher antibody levels for App than those born to parity ≥5 sows (P 0.05). Pigs in F1 had lower antibody levels for App but higher antibody levels for SIV than F2 and F3 pigs (P 0.05), except for increased antibody levels for Mhyo when EP-like lesions were present (P = 0.006).
Conclusion
Results indicate that offspring from primiparous sows develop higher antibody levels for App IV toxin when exposed to this disease and that enforcement of a strict all-in/all-out production system would reduce on-farm disease circulation. A high percentage of pigs were affected with EP-like lesions which were associated with higher antibody levels for Mhyo
Estimating the Effect of Respiratory Disease on Production Performance in Farrow-to-Finish Pig Farms
peer-reviewedBackground Respiratory disease is one of the most important factors impacting pig production
worldwide. However, the literature highlights the multitude of confounding factors complicating the clear
attribution of growth impairment to respiratory disease, and the extrapolation of the effects of respiratory
disease to a wider population has not been thoroughly researched. The objective of this study was to
estimate the impact of respiratory disease on production performance in a subset of 56 Irish farrow-to-
nish
pig farms. Proxies for respiratory disease status such as serology for four major pathogens
(inuenza
A virus, porcine reproductive and respiratory syndrome virus, Mycoplasma hyopneumoniae and
Actinobacillus pleuropneumoniae ), slaughter checks (pleurisy, pneumonia, lung abscesses, pericarditis
and liver milk spots) and vaccination information were used as predictors for production performance.
Results The models to estimate production performance from serology, slaughter checks, and
vaccination were able to explain the variability of weaner and nisher
mortality by 26 and 20%,
respectively, and average daily feed intake (ADFI), average daily gain (ADG) and age at slaughter by 47,
40 and 41%, respectively. Feed conversion ratio and sow performance were not explained by the studied
predictors.
Conclusions The models tted,
especially those for ADFI, ADG and age at slaughter, emphasize the
usefulness of sourcing information at different levels to understand the impact of farm health status on
pig performance, and highlight the impact of respiratory disease on production performance
Detrimental incorporation of excess Cenp-A/Cid and Cenp-C into Drosophila centromeres is prevented by limiting amounts of the bridging factor Cal1
Propagation of centromere identity during cell cycle progression in higher eukaryotes depends critically on the faithful incorporation of a centromere-specific histone H3 variant encoded by CENPA in humans and cid in Drosophila. Cenp-A/Cid is required for the recruitment of Cenp-C, another conserved centromere protein. With yeast three-hybrid experiments, we demonstrate that the essential Drosophila centromere protein Cal1 can link Cenp-A/Cid and Cenp-C. Cenp-A/Cid and Cenp-C interact with the N- and C-terminal domains of Cal1, respectively. These Cal1 domains are sufficient for centromere localization and function, but only when linked together. Using quantitative in vivo imaging to determine protein copy numbers at centromeres and kinetochores, we demonstrate that centromeric Cal1 levels are far lower than those of Cenp-A/Cid, Cenp-C and other conserved kinetochore components, which scale well with the number of kinetochore microtubules when comparing Drosophila with budding yeast. Rather than providing a stoichiometric link within the mitotic kinetochore, Cal1 limits centromeric deposition of Cenp-A/Cid and Cenp-C during exit from mitosis. We demonstrate that the low amount of endogenous Cal1 prevents centromere expansion and mitotic kinetochore failure when Cenp-A/Cid and Cenp-C are present in excess
Mechanism of bacterial interference with TLR4 signaling by Brucella TIR-domain-containing protein TcpB
Upon activation of Toll-like receptors (TLRs), cytoplasmic Toll/interleukin-1 receptor (TIR) domains of the receptors undergo homo- or hetero-dimerization. This in turn leads to the recruitment of adaptor proteins, activation of transcription factors, and the secretion of pro-inflammatory cytokines. Recent studies have described the TIR-domain-containing protein from Brucella melitensis, TcpB (BtpA/Btp1), to be involved in virulence and suppression of host innate immune responses. TcpB interferes with TLR4 and TLR2 signaling pathways by a mechanism that remains controversial. In this study, we show using co-immunoprecipitation analyses that TcpB interacts with MAL, MyD88, and TLR4, but interferes only with the MAL:TLR4 interaction. We present the crystal structure of the TcpB TIR domain, which reveals significant structural differences in the loop regions compared to other TIR domain structures. We demonstrate that TcpB forms a dimer in solution, and the crystal structure reveals the dimerization interface, which we validate by mutagenesis and biophysical studies. Our study advances the understanding of the molecular mechanisms of host immunosuppression by bacterial pathogens
Phycodnavirus Potassium Ion Channel Proteins Question the Virus Molecular Piracy Hypothesis
Phycodnaviruses are large dsDNA, algal-infecting viruses that encode many genes with homologs in prokaryotes and eukaryotes. Among the viral gene products are the smallest proteins known to form functional K+ channels. To determine if these viral K+ channels are the product of molecular piracy from their hosts, we compared the sequences of the K+ channel pore modules from seven phycodnaviruses to the K+ channels from Chlorella variabilis and Ectocarpus siliculosus, whose genomes have recently been sequenced. C. variabilis is the host for two of the viruses PBCV-1 and NY-2A and E. siliculosus is the host for the virus EsV-1. Systematic phylogenetic analyses consistently indicate that the viral K+ channels are not related to any lineage of the host channel homologs and that they are more closely related to each other than to their host homologs. A consensus sequence of the viral channels resembles a protein of unknown function from a proteobacterium. However, the bacterial protein lacks the consensus motif of all K+ channels and it does not form a functional channel in yeast, suggesting that the viral channels did not come from a proteobacterium. Collectively, our results indicate that the viruses did not acquire their K+ channel-encoding genes from their current algal hosts by gene transfer; thus alternative explanations are required. One possibility is that the viral genes arose from ancient organisms, which served as their hosts before the viruses developed their current host specificity. Alternatively the viral proteins could be the origin of K+ channels in algae and perhaps even all cellular organisms
Circumstellar disks and planets. Science cases for next-generation optical/infrared long-baseline interferometers
We present a review of the interplay between the evolution of circumstellar
disks and the formation of planets, both from the perspective of theoretical
models and dedicated observations. Based on this, we identify and discuss
fundamental questions concerning the formation and evolution of circumstellar
disks and planets which can be addressed in the near future with optical and
infrared long-baseline interferometers. Furthermore, the importance of
complementary observations with long-baseline (sub)millimeter interferometers
and high-sensitivity infrared observatories is outlined.Comment: 83 pages; Accepted for publication in "Astronomy and Astrophysics
Review"; The final publication is available at http://www.springerlink.co
Why We Sleep: The Temporal Organization of Recovery
Why we sleep seems like a simple question, yet it has baffled scientists for generations. Based on recent data, Emmanuel Mignot argues that the function of sleep is essentially a resilient form of cellular recovery, organized anatomically and temporally by natural evolution, that has taken on additional functions over time
A Novel Method of Characterizing Genetic Sequences: Genome Space with Biological Distance and Applications
Most existing methods for phylogenetic analysis involve developing an evolutionary model and then using some type of computational algorithm to perform multiple sequence alignment. There are two problems with this approach: (1) different evolutionary models can lead to different results, and (2) the computation time required for multiple alignments makes it impossible to analyse the phylogeny of a whole genome. This motivates us to create a new approach to characterize genetic sequences.To each DNA sequence, we associate a natural vector based on the distributions of nucleotides. This produces a one-to-one correspondence between the DNA sequence and its natural vector. We define the distance between two DNA sequences to be the distance between their associated natural vectors. This creates a genome space with a biological distance which makes global comparison of genomes with same topology possible. We use our proposed method to analyze the genomes of the new influenza A (H1N1) virus, human rhinoviruses (HRV) and mammalian mitochondrial. The result shows that a triple-reassortant swine virus circulating in North America and the Eurasian swine virus belong to the lineage of the influenza A (H1N1) virus. For the HRV and mammalian mitochondrial genomes, the results coincide with biologists' analyses.Our approach provides a powerful new tool for analyzing and annotating genomes and their phylogenetic relationships. Whole or partial genomes can be handled more easily and more quickly than using multiple alignment methods. Once a genome space has been constructed, it can be stored in a database. There is no need to reconstruct the genome space for subsequent applications, whereas in multiple alignment methods, realignment is needed to add new sequences. Furthermore, one can make a global comparison of all genomes simultaneously, which no other existing method can achieve
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